"This news media focus on support held true whether the stories were reported in news articles or opinion pieces, and was also the case across nearly all media sectors studied," said the report's authors. "All three of the major cable networks, for instance, had more stories with significantly more supportive statements than opposing, including Fox News."

The level of support conveyed in the news media goes much further than the level seen in public opinion surveys.

For example, according to a recent NBC/ WSJ poll, 51 percent of Americans support gay marriage but only 47 percent believe the federal definition of marriage should include same-sex marriage, and 48 percent say they still believe marriage should be between a man and a woman.

The new report also noted that Twitter postings on the subject were nearly evenly split between support and opposition for the measure, "aligning more closely with public opinion than with the news media."